A piston for a diesel engine is provided. The piston includes a thermal barrier coating applied to a crown formed of steel. A layer of a metal bond material is first applied to a combustion surface of the crown, followed by a gradient structure including a mixture of the metal bond material and a ceramic material, followed by a layer of the ceramic material. The ceramic material includes at least one of ceria, ceria stabilized zirconia, yttria stabilized zirconia, calcia stabilized zirconia, magnesia stabilized zirconia, and zirconia stabilized by another oxide. The thermal barrier coating is applied by a thermal spray process or HVOF. The thermal barrier coating has a porosity of 2% by vol. to 25% vol., based on the total volume of the thermal barrier coating, a thickness of less than 1 mm, and a thermal conductivity of less than 1.00 W/m·K.